U.S. Pat. No. 6,503,451 discloses an oxygenator constructed for gas exchange that utilizes a multiplicity of hollow fiber membranes. This oxygenator includes a housing, a hollow fiber membrane bundle received in the housing, blood inlet and outlet ports, and gas inlet and outlet ports. The oxygenator effects gas exchange (i.e., oxygenation and carbon-dioxide removal) between blood and gas through the hollow fiber membranes.
The construction of this oxygenator makes it susceptible to the possibility that bubbles will become mingled with the blood passing through the blood inlet port. In such a case, it would be desirable to remove the bubbles by virtue of the hollow fiber membrane bundle.
However, the hollow fiber membrane bundle is not fabricated with the intention of removing bubbles, but rather is designed for efficient gas exchange. Hence, the hollow fiber bundle is not well suited to being able to sufficiently effect bubble removal. Thus, it is possible that bubbles remaining in the blood exiting through the blood outlet port will be conveyed downstream of the oxygenator. For this reason, it is known to use an arterial filter for bubble removal on the arterial line from the oxygenator to the patient.